console.log(Object.prototype.toString.call(''));
console.log(Object.prototype.toString.call(1));
console.log(Object.prototype.toString.call(undefined));
console.log(Object.prototype.toString.call([]));
console.log(Object.prototype.toString.call({}));
console.log(Object.prototype.toString.call(null));

let myExport = {};
console.log(Object.prototype.toString.call(myExport)); // [object Object]
Object.defineProperty(myExport, Symbol.toStringTag, {
    value: 'Module',
    enumerable: false, // 是否可枚举  for in中使用
    configurable: false, // 是否可以通过一个delete关键字 删除
})
console.log(Object.prototype.toString.call(myExport));  // [object Module]
